1. Field of the Invention
The present invention generally relates to a method for automatically establishing a connection between a master terminal and a slave device, and more particularly to a method and system for automatically establishing a connection between a master terminal and a slave device using Bluetooth® (hereinafter “Bluetooth”) communication.
2. Description of the Related Art
A Bluetooth system is constructed with one master Bluetooth device and multiple slave devices. A master is a Bluetooth device for generating a service and slaves are Bluetooth devices for receiving a service dependent on the master, i.e., the Bluetooth device for generating the service becomes the master. When a service is generated from a specific Bluetooth device, the master that generates the service performs an inquiry process to acquire synchronization with the slaves in a standby state, that is, to determine whether the peripheral slaves are present.
On the other hand, a method for establishing a connection between a master device and other slave devices using Bluetooth communication will be described with reference to FIG. 1. FIG. 1 is a typical flow diagram illustrating signals transmitted and received between a master 10 and a slave 11. In FIG. 1, the slave 11 is at least one Bluetooth device.
First, when the slave 11 is initialized, the slave 11 is set to inquiry scan mode as in step 20. The master 10 makes an inquiry to determine whether peripheral slaves 11 are present in step 30. That is, when a user searches for the peripheral slaves 11 using the master 10, the master 10 starts searching for the peripheral slaves 11 by making the inquiry. All slaves 11 operating in discoverable mode send inquiry responses, in response to the inquiry in step 40, to the master 10. At this time, a searched slave 11 includes its own information in a Frequency Hop Synchronization (FHS) packet and then sends the FHS packet to the master 10. For example, the information includes a Bluetooth Device Address (BD_ADDR), Clock Information (CLKN), an error detection and correction signal or Bose-Chaudhuri-Hocquenghem (BCH) code, etc.
The master 10 displays a list of addresses of all searched slaves 11 upon receiving the inquiry responses from the peripheral slaves 11 in step 50. When the addresses of the searched slaves 11 are displayed on a search image, the user can press a connect button to select an address of a target slave to be connected. Then, the master 10 determines whether a specific slave address is selected in step 60. If the specific slave address is selected, the master 10 displays a password input window on its search image. When the user inputs a password, the master 10 sequentially performs paging and pairing processes with the target slave to be connected. While performing a page scan mode as in step 70, the slave 11 detects that the master 10 starts paging in step 80. Through this paging process, the master 10 acquires hopping sequence synchronization with the slave 11 using an address, clock information, and the like. The slave 11 is actually connected to the master 10 in step 90.
As described above, the Bluetooth connection process is divided into an inquiry process in which a master sends an inquiry to search for slaves and a paging process in which the master attempts an actual connection with a target slave. However, the Bluetooth connection process divided into the two processes may be troublesome to the user. In addition, the user should wait for a long time until the connection with the target slave is established.
The master must perform a process of acquiring a target slave address for a connection with a target slave. For example, if a mono headset without a special screen is the master, the mono headset must send searched slave addresses to an external device connected via a wired link such that target slave addresses can be detected. When a liquid crystal display of the external device displays the searched slave addresses, a user can view the searched slave addresses.
After an inquiry is made as described above, inquiry responses may be received from a significant number of slaves. Since an address list should be created and displayed on the basis of the inquiry responses, a user must wait for the address list to be received in an idle screen state. This is very inconvenient for the user. In addition, when a Bluetooth device has a small Liquid Crystal Display, (LCD) the user must retrieve addresses one by one while scrolling. When no liquid crystal display is provided, an additional procedure should be performed to retrieve a target slave address and may be troublesome to the user.